Field of the Invention
At least an embodiment of the present invention relates to a solenoid valve device used in, for example, an automatic transmission of a vehicle.
Description of the Related Art
A control valve is typically provided in an automatic transmission of a vehicle to control a transmission system. The control valve controls the transmission system by supplying a hydraulic pressure of a predetermined magnitude to the transmission system or stopping the supply using a solenoid valve device.
Such solenoid valve devices are described in, for example, JP-A 2003-207069 and JP-A 2002-188744. The solenoid valve device described in JP-A 2003-207069 is an on-off solenoid valve, and this solenoid valve device includes a nozzle in which a valve body is accommodated, and a solenoid to drive the valve body. The solenoid includes a cylindrical case, and a bobbin around which a coil is wound, a fixed core, and a rod pin arranged to reciprocate in a center of the coil are accommodated in the cylindrical case. In the solenoid valve device, the coil of the solenoid is energized to cause the rod pin to reciprocate, and a tip of the rod pin causes opening and closing of the valve body.
In the solenoid valve device described in JP-A 2003-207069, the bobbin around which the coil of the solenoid is wound and the nozzle in which the valve body is accommodated are integrally molded of a resin. The fixed core (also referred to as a yoke) and the valve body are integrally incorporated in the resin by an insert molding process.
The flow characteristic of the solenoid valve device generally needs to be adjusted in accordance with the purpose of the solenoid valve device or the like. In order to adjust the flow characteristic of the solenoid valve device during a process of manufacturing the solenoid valve device, one or both of the following measures, for example, are taken:
(1) changing the dimensions and shape of an oil passage on the valve body side; and
(2) changing the number of turns of the coil on the bobbin side and the shape of the bobbin side, for example.
However, in the case where the bobbin and the nozzle are integrally molded of the resin as in the solenoid valve device described in JP-A 2003-207069, taking even only one of the above measures (1) and (2) would require a specially-designed mold, making an operation of changing the flow characteristic cumbersome.
In particular, in the case where the solenoid valve device is attached to a control valve, not only flow adjustment is necessary, but also an attachment structure for attachment of the solenoid valve device may vary between different types of control valves. For example, the following attachment structures for attachment holes defined in control valves are known.
(3) A nozzle with an O-ring fitted to an outer circumference thereof is fitted into the attachment hole, with the result that a gap between the nozzle and a wall surface of the attachment hole is sealed with the O-ring.
(4) A metal member is used as an entire nozzle or an outer circumferential portion of the nozzle to improve accuracy in an outside diameter of the nozzle, and the nozzle is tightly fitted into the attachment hole without use of a sealing member such as, for example, an O-ring.
Even in the case where such different attachment structures for control valves are required, it has been necessary to manufacture resin-molded articles including specially-designed nozzles in related art.
Standardization of parts has been proposed for the case where solenoid valve devices having different characteristics are manufactured in accordance with required specifications. According to the invention described in JP-A 2002-188744, for example, a nozzle and a bobbin portion are integrally molded of a resin to define a common part, and this common part is used for different cores and rod pin portions, which are designed in accordance with required specifications. However, in the solenoid valve device described in JP-A 2002-188744, a coil portion and a nozzle portion, which constitute a factor that affects the flow characteristic, are integral with each other, and therefore, the operation of changing the flow characteristic is still cumbersome. In addition, the invention described in JP-A 2002-188744 is not able to cope with the case where different attachment structures for control valves, such as the attachment structures (3) and (4) described above, are required.
At least an embodiment of the present invention is able to cope with a change in a flow characteristic of a solenoid valve device, and a change in an attachment structure for a control valve, with a simple structure, for example.